Diffusion in Metallen unter dem Einfluß von hohen mechanischen Spannungen und Beschleunigungen

Weller, A.

Book/Report

FZJ-2018-02348

Diffusion in Metallen unter dem Einfluß von hohen mechanischen Spannungen und Beschleunigungen

Weller, A. (Corresponding author)FZJ*

1984
Kernforschungsanlage Jülich, Verlag Jülich

Jülich : Kernforschungsanlage Jülich, Verlag, Berichte der Kernforschungsanlage Jülich 1913, 105 p. (1984)

Please use a persistent id in citations: http://hdl.handle.net/2128/18035

Report No.: Juel-1913

Abstract: Theoretical calculations show that the diffusion of substitutional atoms in metals should be enhanced by mechanical stress. High mechanical stresses can be produced by fast rotation of the sample. The influence of centrifugal forces on a single diffusive jump can in most cases be neglected, since they are very small compared with inner-atomic forces. In a long ranging diffusion, however, these effects can lead to a significant change of the concentration distribution. In order to investigate the influence of mechanical stress and centrifugal forces on diffusion an apparatus was constructed in which ferromagnetic samples with a diameter of 15 . . .20 mm can be magnetically suspended in high vacuum. The cylindrical samples are rotated about the axis of symmetry and they can be heated by radiation up to 850 K. The maximum frequency of rotation is determined only by the strength of the material. For the precise determination of the sample temperature a new method based on the radiative interaction of the sample with its environment was developed. Measurements of the diffusion coefficient were carried out using iron cylinders covered with a thin layer of aluminium. The evaluation of the diffusion profile as determined by AES showed that the influence of mechanical stress was too small to be detected by the experimental arrangement used. High centrifugal fields can be used as a tool for studying fast diffusion. For this purpose, preliminary experiments concerning the feasibility of the method were carried through.

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